www.vaisala.com
Vaisala Weather Radar WRK200
Dual Polarization Adds
New Dimension
The Vaisala Weather Radar
WRK200 is a dual polarization C-band
Klystron Doppler Weather Radar. The
radar operates in either Simultaneous
Transmit and Receive of H and V (STAR)
mode or Linear Depolarization Mode
(LDR) mode , during which H alone
is transmitted and both are received.
STAR mode enables use of the high
sensitivity power estimator increasing
detectability by up to 10 dB versus
the competition. The polarization
variables, depending on the mode, are
ZDR, RHOHV, PHIDP, KDP and LDR.
However, the goal of polarization radar
is not only to produce and display
these outputs; it is also to expand
the capabilities of the radar for the
operational forecaster.
The WRK200 provides the following
benefits:
• Hydrometeor identification
• Attenuation correction
• Data quality improvement
• Improved rainfall estimates,
based on KDP
S-Band Performance at
a C-Band Price
Attenuation by intervening heavy
precipitation has been a long-standing
problem with C-band weather radars,
making S-band radars preferable,
especially in tropical environments
where heavy rain is common. However,
with dual polarization, the radar
performs accurate, real-time attenuation
corrections. The benefit is that you
can obtain the same precipitation
measurement accuracy using the
WRK200 as with an S-band system that
costs typically two or three times more.
More Accurate
Precipitation Measurement
Eliminating non-meteorological
targets and correcting attenuation can
substantially improve precipitation
measurement. However, the WRK200
Features/Benefits
▪
Vaisala’s light-weight, semi-
yoke-style pedestal
▪
1 degree beamwidth low side
lobe antenna
▪
High sensitivity mode
processing to recover
sensitivity loss in STAR mode
▪
>35 dB integrated cross-
polarization isolation
▪
Image rejection >80 dB
(>100dB with Vaisala WG
filters).
▪
Dynamic range > 99 dB
(2
µ
s pulse)
▪
Feed forward control loop
to allow extremely fast and
precise antenna movement
▪
Dual channel digital IF receiver
▪
Precision horizontal and
vertical beam matching
▪
Built around Vaisala Sigmet
RVP900 signal processor
▪
Integral flat screen display for
local maintenance
▪
Remote control/monitoring
▪
Rainfall estimation based on
KDP
▪
Accurate attenuation
correction
▪
250 kW klystron transmitter
with low-maintenance solid-
state modulator
▪
Option: Built-in dual channel
receiver calibration
goes further by providing KDP-based
measurement of the precipitation
rate. Unlike the reflectivity (Z),
KDP is directly proportional to the
precipitation rate, independent of the
radar calibration and unbiased by
intervening clutter or partial beam
blockage. This makes the KDP very
robust in measuring moderate and
heavy rain.
